Maarten Lankhorst also contributed to this driver.

ZBIAS was removed in d3d9 and replaced with DEPTHBIAS. Currently
wined3d implements both independently which will cause trouble if we
want to set the depthbias value depending on the depth stencil format.

This ensures that the thread can be notified when the clip rectangle is reset.

user32: Pass a NULL rectangle in the ClipCursor entry point when clipping is reset because of focus change.